1. Field of the Invention
The present invention relates to stepping motors and the use thereof with a hollow shaft and a ball slide in order to provide a linear actuator. By the term "ball slide" I mean to include apparatus such as a tubular housing having ball bearings at the inside surface thereof within which a bar may be moved longitudinally in contact with the ball bearings.
2. Description of the Prior Art
Conventional linear actuators make use of a stepping motor which imparts rotary movement to a screw. A nut surrounding the screw and restrained from rotation is given linear movement by the rotation of the screw. Alternatively, an electric motor can be used to rotate a nut. A screw which is engaged by the nut is given linear movement by the rotation of the nut.
Each such system requires a specific nut and a specific screw suitable for use with the specific nut. This requirement is not desirable, because various grades of screws are commercially available at present and a given stepping motor should be usable with a variety of screws.
An example of conventional linear actuator is shown in U.S. Pat. No. 4,693,131 to Teramachi.